device/device.h: Drop multiple links

Multiple links are unused throughout the tree and make the code more
confusing as an iteration over all busses is needed to get downstream
devices. This also not done consistently e.g. the allocator does not
care about multiple links on busses. A better way of dealing multiple
links below a device is to feature dummy devices with each their
respective bus.

This drops the sconfig capability to declare the same device multiple
times which was previously used to declare multiple links.

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: Iab6fe269faef46ae77ed1ea425440cf5c7dbd49b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78328
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jincheng Li <jincheng.li@intel.com>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>

1 files changed, 31 insertions, 48 deletions

diff --git a/src/device/device.c b/src/device/device.c
index d877e14eab..743a3af6c2 100644
--- a/src/device/device.c
+++ b/src/device/device.c
@@ -187,13 +187,11 @@ static void read_resources(struct bus *bus)
 {
 	struct device *curdev;
 
-	printk(BIOS_SPEW, "%s %s segment group %d bus %d link: %d\n", dev_path(bus->dev),
-	       __func__, bus->segment_group, bus->secondary, bus->link_num);
+	printk(BIOS_SPEW, "%s %s segment group %d bus %d\n", dev_path(bus->dev),
+	       __func__, bus->segment_group, bus->secondary);
 
 	/* Walk through all devices and find which resources they need. */
 	for (curdev = bus->children; curdev; curdev = curdev->sibling) {
-		struct bus *link;
-
 		if (!curdev->enabled)
 			continue;
 
@@ -207,12 +205,12 @@ static void read_resources(struct bus *bus)
 		curdev->ops->read_resources(curdev);
 
 		/* Read in the resources behind the current device's links. */
-		for (link = curdev->link_list; link; link = link->next)
-			read_resources(link);
+		if (curdev->link_list)
+			read_resources(curdev->link_list);
 	}
 	post_log_clear();
-	printk(BIOS_SPEW, "%s %s segment group %d bus %d link: %d done\n",
-	       dev_path(bus->dev), __func__, bus->segment_group, bus->secondary, bus->link_num);
+	printk(BIOS_SPEW, "%s %s segment group %d bus %d done\n",
+	       dev_path(bus->dev), __func__, bus->segment_group, bus->secondary);
 }
 
 struct device *vga_pri = NULL;
@@ -301,8 +299,8 @@ void assign_resources(struct bus *bus)
 {
 	struct device *curdev;
 
-	printk(BIOS_SPEW, "%s %s, segment group %d bus %d link: %d\n",
-	       dev_path(bus->dev), __func__, bus->segment_group, bus->secondary, bus->link_num);
+	printk(BIOS_SPEW, "%s %s, segment group %d bus %d\n",
+	       dev_path(bus->dev), __func__, bus->segment_group, bus->secondary);
 
 	for (curdev = bus->children; curdev; curdev = curdev->sibling) {
 		if (!curdev->enabled || !curdev->resource_list)
@@ -317,8 +315,8 @@ void assign_resources(struct bus *bus)
 		curdev->ops->set_resources(curdev);
 	}
 	post_log_clear();
-	printk(BIOS_SPEW, "%s %s, segment group %d bus %d link: %d done\n",
-	       dev_path(bus->dev), __func__, bus->segment_group, bus->secondary, bus->link_num);
+	printk(BIOS_SPEW, "%s %s, segment group %d bus %d done\n",
+	       dev_path(bus->dev), __func__, bus->segment_group, bus->secondary);
 }
 
 /**
@@ -336,7 +334,6 @@ void assign_resources(struct bus *bus)
 static void enable_resources(struct bus *link)
 {
 	struct device *dev;
-	struct bus *c_link;
 
 	for (dev = link->children; dev; dev = dev->sibling) {
 		if (dev->enabled && dev->ops && dev->ops->enable_resources) {
@@ -346,8 +343,8 @@ static void enable_resources(struct bus *link)
 	}
 
 	for (dev = link->children; dev; dev = dev->sibling) {
-		for (c_link = dev->link_list; c_link; c_link = c_link->next)
-			enable_resources(c_link);
+		if (dev->link_list)
+			enable_resources(dev->link_list);
 	}
 	post_log_clear();
 }
@@ -394,17 +391,15 @@ static void scan_bus(struct device *busdev)
 
 	do_scan_bus = 1;
 	while (do_scan_bus) {
-		struct bus *link;
+		struct bus *link = busdev->link_list;
 		busdev->ops->scan_bus(busdev);
 		do_scan_bus = 0;
-		for (link = busdev->link_list; link; link = link->next) {
-			if (link->reset_needed) {
-				if (reset_bus(link))
-					do_scan_bus = 1;
-				else
-					busdev->bus->reset_needed = 1;
-			}
-		}
+		if (!link || !link->reset_needed)
+			continue;
+		if (reset_bus(link))
+			do_scan_bus = 1;
+		else
+			busdev->bus->reset_needed = 1;
 	}
 
 	scan_time = stopwatch_duration_msecs(&sw);
@@ -523,13 +518,11 @@ void dev_configure(void)
  */
 void dev_enable(void)
 {
-	struct bus *link;
-
 	printk(BIOS_INFO, "Enabling resources...\n");
 
 	/* Now enable everything. */
-	for (link = dev_root.link_list; link; link = link->next)
-		enable_resources(link);
+	if (dev_root.link_list)
+		enable_resources(dev_root.link_list);
 
 	printk(BIOS_INFO, "done.\n");
 }
@@ -553,8 +546,7 @@ static void init_dev(struct device *dev)
 		long init_time;
 
 		if (dev->path.type == DEVICE_PATH_I2C) {
-			printk(BIOS_DEBUG, "smbus: %s[%d]->",
-			       dev_path(dev->bus->dev), dev->bus->link_num);
+			printk(BIOS_DEBUG, "smbus: %s->", dev_path(dev->bus->dev));
 		}
 
 		printk(BIOS_DEBUG, "%s init\n", dev_path(dev));
@@ -572,7 +564,6 @@ static void init_dev(struct device *dev)
 static void init_link(struct bus *link)
 {
 	struct device *dev;
-	struct bus *c_link;
 
 	for (dev = link->children; dev; dev = dev->sibling) {
 		post_code(POSTCODE_BS_DEV_INIT);
@@ -580,10 +571,9 @@ static void init_link(struct bus *link)
 		init_dev(dev);
 	}
 
-	for (dev = link->children; dev; dev = dev->sibling) {
-		for (c_link = dev->link_list; c_link; c_link = c_link->next)
-			init_link(c_link);
-	}
+	for (dev = link->children; dev; dev = dev->sibling)
+		if (dev->link_list)
+			init_link(dev->link_list);
 }
 
 /**
@@ -594,16 +584,14 @@ static void init_link(struct bus *link)
  */
 void dev_initialize(void)
 {
-	struct bus *link;
-
 	printk(BIOS_INFO, "Initializing devices...\n");
 
 	/* First call the mainboard init. */
 	init_dev(&dev_root);
 
 	/* Now initialize everything. */
-	for (link = dev_root.link_list; link; link = link->next)
-		init_link(link);
+	if (dev_root.link_list)
+		init_link(dev_root.link_list);
 	post_log_clear();
 
 	printk(BIOS_INFO, "Devices initialized\n");
@@ -633,15 +621,13 @@ static void final_dev(struct device *dev)
 static void final_link(struct bus *link)
 {
 	struct device *dev;
-	struct bus *c_link;
 
 	for (dev = link->children; dev; dev = dev->sibling)
 		final_dev(dev);
 
-	for (dev = link->children; dev; dev = dev->sibling) {
-		for (c_link = dev->link_list; c_link; c_link = c_link->next)
-			final_link(c_link);
-	}
+	for (dev = link->children; dev; dev = dev->sibling)
+		if (dev->link_list)
+			final_link(dev->link_list);
 }
 /**
  * Finalize all devices in the global device tree.
@@ -651,16 +637,13 @@ static void final_link(struct bus *link)
  */
 void dev_finalize(void)
 {
-	struct bus *link;
-
 	printk(BIOS_INFO, "Finalize devices...\n");
 
 	/* First call the mainboard finalize. */
 	final_dev(&dev_root);
 
 	/* Now finalize everything. */
-	for (link = dev_root.link_list; link; link = link->next)
-		final_link(link);
+	final_link(dev_root.link_list);
 
 	printk(BIOS_INFO, "Devices finalized\n");
 }